Semiconductor structure and method of fabricating the same

ABSTRACT

A package structure including a first semiconductor die, a second semiconductor die, first conductive pillars and a first insulating encapsulation is provided. The first semiconductor die includes a semiconductor substrate, an interconnect structure and a first redistribution circuit structure. The semiconductor substrate includes a first portion and a second portion disposed on the first portion.The interconnect structure is disposed on the second portion, the first redistribution circuit structure is disposed on the interconnect structure, and the lateral dimension of the first portion is greater than the lateral dimension of the second portion. The second semiconductor die is disposed on the first semiconductor die. The first conductive pillars are disposed on the first redistribution circuit structure of the first semiconductor die. The first insulating encapsulation is disposed on the first portion. The first insulating encapsulation laterally encapsulates the second semiconductor die, the first conductive pillars and the second portion.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional application of and claims the prioritybenefit of U.S. application Ser. No. 16/881,002, filed on May 22, 2020,now allowed. The entirety of each of the above-mentioned patentapplications is hereby incorporated by reference herein and made a partof this specification.

BACKGROUND

The semiconductor industry has experienced rapid growth due tocontinuous improvements in the integration density of a variety ofelectronic components (e.g., transistors, diodes, resistors, capacitors,etc.). For the most part, this improvement in integration density hascome from repeated reductions in minimum feature size, which allows morecomponents to be integrated into a given area. As the demand forminiaturization, higher speed and greater bandwidth, as well as lowerpower consumption and latency has grown recently, there has grown a needfor smaller and more creative packaging techniques of semiconductordies. Currently, System-on-Integrated-Circuit (SoIC) components arebecoming increasingly popular for their multi-functions and compactness.However, there are challenges related to packaging process of the SoICcomponents.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of the present disclosure are best understood from the followingdetailed description when read with the accompanying figures. It isnoted that, in accordance with the standard practice in the industry,various features are not drawn to scale. In fact, the dimensions of thevarious features may be arbitrarily increased or reduced for clarity ofdiscussion.

FIG. 1A through FIG. 1F are cross-sectional views schematicallyillustrating a process flow for fabricating a top tier semiconductor diein accordance with some embodiments of the present disclosure.

FIG. 2A through FIG. 2H are cross-sectional views schematicallyillustrating a process flow for fabricating a package structure inaccordance with some embodiments of the present disclosure.

FIG. 3 is an enlarged cross-sectional view of the region X illustratedin FIG. 2E.

FIG. 4 is an enlarged cross-sectional view of the region Y illustratedin FIG. 2G.

FIG. 5A through FIG. 5G are cross-sectional views schematicallyillustrating a process flow for fabricating a package structure inaccordance with some alternative embodiments of the present disclosure.

FIG. 6 is an enlarged cross-sectional view of the region Z illustratedin FIG. 5G.

DETAILED DESCRIPTION

The following disclosure provides many different embodiments, orexamples, for implementing different features of the provided subjectmatter. Specific examples of components and arrangements are describedbelow to simplify the present disclosure. These are, of course, merelyexamples and are not intended to be limiting. For example, the formationof a first feature over or on a second feature in the description thatfollows may include embodiments in which the first and second featuresare formed in direct contact, and may also include embodiments in whichadditional features may be formed between the first and second features,such that the first and second features may not be in direct contact. Inaddition, the present disclosure may repeat reference numerals and/orletters in the various examples. This repetition is for the purpose ofsimplicity and clarity and does not in itself dictate a relationshipbetween the various embodiments and/or configurations discussed.

Further, spatially relative terms, such as “beneath,” “below,” “lower,”“above,” “upper” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. The spatiallyrelative terms are intended to encompass different orientations of thedevice in use or operation in addition to the orientation depicted inthe figures. The apparatus may be otherwise oriented (rotated 90 degreesor at other orientations) and the spatially relative descriptors usedherein may likewise be interpreted accordingly.

Other features and processes may also be included. For example, testingstructures may be included to aid in the verification testing of the 3Dpackaging or 3DIC devices. The testing structures may include, forexample, test pads formed in a redistribution layer or on a substratethat allows the testing of the 3D packaging or 3DIC, the use of probesand/or probe cards, and the like. The verification testing may beperformed on intermediate structures as well as the final structure.Additionally, the structures and methods disclosed herein may be used inconjunction with testing methodologies that incorporate intermediateverification of known good dies to increase the yield and decreasecosts.

FIG. 1A through FIG. 1F are cross-sectional views schematicallyillustrating a process flow for fabricating a top tier semiconductor diein accordance with some embodiments of the present disclosure.

Referring to FIG. 1A, a semiconductor wafer W1 including top tiersemiconductor dies 100 arranged in array is provided. The semiconductorwafer W1 may include a semiconductor substrate 110, an interconnectstructure 120 disposed on the semiconductor substrate 110, conductivevias 130 disposed on and electrically connected to the interconnectstructure 120, and solder material layers 140 disposed on top surfacesof the conductive vias 130. The semiconductor substrate 110 may be asilicon substrate including active components (e.g., transistors or thelike) and passive components (e.g., resistors, capacitors, inductors, orthe like) formed therein. The active components and passive componentsare formed in the semiconductor substrate 110 through front end of line(FEOL) fabrication processes of the semiconductor wafer W1. Theinterconnect structure 120 may include interconnect wirings (e.g.,copper interconnect wirings) and dielectric layer stacked alternately,wherein the interconnect wirings of the interconnect structure 120 areelectrically connected to the active components and/or the passivecomponents in the semiconductor substrate 110. The interconnectstructure 120 is formed through back end of line (BEOL) fabricationprocesses of the semiconductor wafer W1. The topmost interconnectwirings may include conductive pads 122, and the conductive pads 122 maybe aluminum pads, copper pads, or other suitable metallic pads. Theinterconnect structure 120 may further include a passivation layer 124,wherein the conductive pads 122 are partially covered by the passivationlayer 124. In other words, the conductive pads 122 are partiallyrevealed from the openings defined in the passivation layer 124. Thepassivation 124 may be a silicon oxide layer, a silicon nitride layer, asilicon oxy-nitride layer, or a dielectric layer formed by othersuitable inorganic dielectric materials. The interconnect structure 120may further include a post-passivation layer 126 formed over thepassivation layer 124, wherein the post-passivation layer 126 covers thepassivation layer 124 and the conductive pads 122, the post-passivationlayer 126 includes a plurality of contact openings, and the conductivepads 122 are partially revealed from the contact openings defined in thepost passivation layer 126. The post-passivation layer 126 may be apolyimide (PI) layer, a PBO layer, or a dielectric layer formed by othersuitable organic dielectric materials. In some embodiments, thepost-passivation layer 126 is omitted.

The conductive vias 130 may protrude from the top surface of thepost-passivation layer 126. In some embodiments, the conductive vias 130include copper vias, and the solder material layers 140 include leadfree solder material layers. Furthermore, the conductive vias 130 andthe solder material layers 140 may be formed over the conductive pads122 through one or more plating processes. In some embodiments, a seedlayer (e.g., Ti/Cu seed layer) is formed on the post-passivation layer126 and revealed portions of the conductive pads 122 through a sputterprocess; a patterned photoresist layer is formed on the sputtered seedlayer, wherein the patterned photoresist layer includes openings locatedabove the conductive pads 122 for exposing the sputtered seed layer; oneor more plating processes are performed such that the conductive vias130 and the solder material layers 140 are sequentially plated on thesputtered seed layer exposed by the openings defined in the patternedphotoresist layer; the patterned photoresist layer is stripped; andportions of the sputtered seed layer which are not covered by theconductive vias 130 and the solder material layers 140 are removedthrough an etching process until the post-passivation layer 126 isexposed.

Referring to FIG. 1B, a wafer-level chip probing process may beperformed on the top tier semiconductor dies 100 in the semiconductorwafer W1. Probe cards PC1 may be provided and pressed onto the soldermaterial layers 140 to perform a wafer-level testing such that testedand reliable known good dies (KGDs) among the top tier semiconductordies 100 may be recognized. After performing the wafer-level chipprobing process, testing marks (e.g., indentation) resulted from theprobe pins of the probe cards PC1 may occur on top surfaces of thesolder material layers 140. The solder material layers 140 may protectthe conductive vias 130 from being directly in contact with and theprobe pins of the probe cards PC1.

Referring to FIG. 1C, after performing the wafer-level chip probingprocess, the solder material layers 140 are removed from the topsurfaces of the conductive vias 130. In some embodiments, the soldermaterial layers 140 are removed from the top surfaces of the conductivevias 130 through an etching process. Since the solder material layers140 are removed, the testing marks (e.g., indentation) on the topsurfaces of the solder material layers 140 would not affect thesubsequently performed processes. Due to the etching process forremoving the solder material layers 140, the conductive vias 130 may bepartially etched, and the top surfaces of the conductive vias 130 maybecome doming-like top surfaces. Each conductive via 130 may include abase portion 130 a and a doming portion 130 b disposed on the baseportion 130 a, respectively. For example, the height of the base portion130 a ranges from about 10 micrometers to about 30 micrometers, and themaximum height of the doming portion 130 b ranges from about 2micrometers to about 10 micrometers.

After removing the solder material layers 140 from the top surfaces ofthe conductive vias 130, a protection layer 150 may be conformallyformed over the semiconductor wafer W1 to cover the post-passivationlayer 126 and the conductive vias 130. The protection layer 150 may bein contact with sidewalls of the base portions 130 a, doming-like topsurfaces of the doming portions 130 b and the top surface of thepost-passivation layer 126. The protection layer 150 may be a polyimide(PI) layer, a PBO layer, or a dielectric layer formed by other suitableorganic dielectric materials. The protection layer 150 may be formedthrough chemical vapor deposition (CVD), physical vapor deposition(PVD), dispensing or other suitable film deposition processes.

Referring to FIG. 1C and FIG. 1D, a thinning process of thesemiconductor wafer W1 is performed such that the semiconductorsubstrate 110 of the semiconductor wafer W1 is thinned down. In someembodiments, the semiconductor wafer W1 is flipped upside down, and thesemiconductor substrate 110 is thinned down from a back surface of thesemiconductor wafer W1 through a thinning process. In some embodiments,the semiconductor substrate 110 is thinned down through a mechanicalgrinding process, a chemical mechanical polishing (CMP) process, anetching process, combinations thereof or other suitable removalprocesses. After performing the thinning process of the semiconductorwafer W1, a die attachment film 160 may be attached to the back surfaceof the semiconductor substrate 110.

Referring to FIG. 1E, a frame mount process may be performed such thatthe semiconductor wafer W1 with reduced thickness is mounted on andattached to a frame F through the die attachment film 160. A pre-cutprocess Si is performed along intersected scribe lines SL1 of thesemiconductor wafer W1 such that intersected grooves G1 are formed on afront surface of the semiconductor wafer W1. In some embodiments, thegrooves G1 are formed through a non-contact cutting process performedalong the intersected scribe lines SL1 of the semiconductor wafer W1.For example, the grooves G1 are formed through a laser grooving processperformed along the intersected scribe lines SL1 of the semiconductorwafer W1. The grooves G1 may extend through the interconnect structure120, and portions of the semiconductor substrate 110 are revealed by thegrooves G1.

Referring to FIG. 1E and FIG. 1F, a wafer sawing process S2 is performedfrom the front surface of the semiconductor wafer W1 to saw thesemiconductor wafer W1 and die attachment film 160. The wafer sawingprocess S2 is performed along the grooves G1 or the intersected scribelines SL1 of the semiconductor wafer W1 to obtain singulated top tiersemiconductor dies 100 having ring-shaped grooves G1′. The cutting widthof the pre-cut process S1 may be wider than the cutting width of thewafer sawing process S2. In other words, the maximum lateral dimensionof the grooves G1 may be wider than the cutting width of the wafersawing process S2. In some embodiments, the pre-cut process Si is alaser grooving process while the wafer sawing process S2 is a blade sawprocess, wherein the cutting width of the pre-cut process S1 (e.g., thelaser grooving process) is wider than the cutting width of the wafersawing process S2 (e.g., the blade saw process). Since the cutting widthof the pre-cut process S1 (i.e. the maximum lateral dimension of thegrooves G1) is wider than the cutting width of the wafer sawing processS2, the interconnect structure 120 and the protection layer 150 of eachsingulated top tier semiconductor die 100 may not be in contact with theblade used in the wafer sawing process S2. Accordingly, the pre-cutprocess S1 (i.e. the grooves G1) may protect the interconnect structure120 and the protection layer 150 from being damaged during the wafersawing process S2.

As illustrated in FIG. 1F, the singulated top tier semiconductor die 100may include the semiconductor substrate 110 and the interconnectstructure 120 disposed on the semiconductor substrate 110. The thicknessof the semiconductor substrate 110 may range from about 40 micrometersto about 100 micrometers. The semiconductor substrate 110 may include afirst portion 110 a and a second portion 110 b disposed on the firstportion 110 a, wherein the interconnect structure 120 is disposed on thesecond portion 110 b, and the lateral dimension of the first portion 110a is greater than the lateral dimension of the second portion 110 b. Thelateral dimension of the second portion 110 b and the lateral dimensionof the interconnect structure 120 are determined by the cutting width ofthe pre-cut process S1 (i.e. the maximum lateral dimension of thegrooves G1 or G1′) while the lateral dimension of the first portion 110a is determined by the cutting width of the wafer sawing process S2(e.g., the blade saw process). In some embodiments, the maximum lateraldimension of the grooves G1′ ranges from about 5 micrometers to about 30micrometers, and the depth of the grooves G1′ ranges from about 10micrometers to about 30 micrometers.

FIG. 2A through FIG. 2H are cross-sectional views schematicallyillustrating a process flow for fabricating a package structure inaccordance with some embodiments of the present disclosure. FIG. 3 is anenlarged cross-sectional view of the region X illustrated in FIG. 2E.FIG. 4 is an enlarged cross-sectional view of the region Y illustratedin FIG. 2G.

Referring to FIG. 2A, a semiconductor wafer W2 including bottom tiersemiconductor dies 200 arranged in array is provided. The semiconductorwafer W2 may include a semiconductor substrate 210, an interconnectstructure 220 disposed on the semiconductor substrate 210, aredistribution circuit structure 230 (i.e. a first redistributioncircuit structure) and solder material layers 240 disposed on topsurfaces of the redistribution circuit structure 230. The semiconductorsubstrate 210 may be a silicon substrate including active components(e.g., transistors or the like) and passive components (e.g., resistors,capacitors, inductors, or the like) formed therein. The activecomponents and passive components are formed in the semiconductorsubstrate 210 through front end of line (FEOL) fabrication processes ofthe semiconductor wafer W2. The interconnect structure 220 may includeinterconnect wirings (e.g., copper interconnect wirings) and dielectriclayer stacked alternately, wherein the interconnect wirings of theinterconnect structure 220 are electrically connected to the activecomponents and/or the passive components in the semiconductor substrate210. The interconnect structure 220 is formed through back end of line(BEOL) fabrication processes of the semiconductor wafer W2. The topmostinterconnect wirings may include conductive pads 222, and the conductivepads 222 may be aluminum pads, copper pads, or other suitable metallicpads. The interconnect structure 220 may further include a passivationlayer 224, wherein the conductive pads 222 are partially covered by thepassivation layer 224. In other words, the conductive pads 222 arepartially revealed from the openings defined in the passivation layer224. The passivation 224 may be a silicon oxide layer, a silicon nitridelayer, a silicon oxy-nitride layer, or a dielectric layer formed byother suitable inorganic dielectric materials. The interconnectstructure 220 may further include a post-passivation layer 226 formedover the passivation layer 224, wherein the post-passivation layer 226covers the passivation layer 224 and the conductive pads 222, thepost-passivation layer 226 includes a plurality of contact openings, andthe conductive pads 222 are partially revealed from the contact openingsdefined in the post passivation layer 226. The post-passivation layer226 may be a polyimide (PI) layer, a PBO layer, or a dielectric layerformed by other suitable organic dielectric materials. In someembodiments, the post-passivation layer 226 is omitted.

The redistribution circuit structure 230 may be formed on the postpassivation layer 226 and electrically connected to the conductive pads222 through the contact openings defined in the post passivation layer226. In some embodiments, the redistribution circuit structure 230includes copper redistribution wirings, and the solder material layers240 include lead free solder material layers. Furthermore, theredistribution circuit structure 230 and the solder material layers 240may be formed over the conductive pads 222 through one or more platingprocesses. In some embodiments, a seed layer (e.g., Ti/Cu seed layer) isformed on the post-passivation layer 226 and revealed portions of theconductive pads 222 through a sputter process; a patterned photoresistlayer is formed on the sputtered seed layer, wherein the patternedphotoresist layer includes openings located above the conductive pads222 for exposing the sputtered seed layer; one or more plating processesare performed such that the redistribution circuit structure 230 and thesolder material layers 240 are sequentially plated on the sputtered seedlayer exposed by the openings defined in the patterned photoresistlayer; the patterned photoresist layer is stripped; and portions of thesputtered seed layer which are not covered by the redistribution circuitstructure 230 and the solder material layers 240 are removed through anetching process until the post-passivation layer 226 is exposed.

Referring to FIG. 2B, a wafer-level chip probing process may beperformed on the bottom tier semiconductor dies 200 in the semiconductorwafer W2. Probe cards PC2 may be provided and pressed onto the soldermaterial layers 240 to perform a wafer-level testing such that testedand reliable known good dies (KGDs) among the bottom tier semiconductordies 200 may be recognized. After performing the wafer-level chipprobing process, testing marks (e.g., indentation) resulted from theprobe pins of the probe cards PC2 may occur on top surfaces of thesolder material layers 240. The solder material layers 240 may protectthe redistribution circuit structure 230 from being directly in contactwith and the probe pins of the probe cards PC2.

Referring to FIG. 2C, after performing the wafer-level chip probingprocess, the solder material layers 240 are removed from the topsurfaces of the redistribution circuit structure 230. In someembodiments, the solder material layers 240 are removed from the topsurfaces of the redistribution circuit structure 230 through an etchingprocess. Since the solder material layers 240 are removed, the testingmarks (e.g., indentation) on the top surfaces of the solder materiallayers 240 would not affect the subsequently performed processes. Asillustrated in FIG. 3, due to the etching process for removing thesolder material layers 240, the redistribution circuit structure 230 maybe partially etched and the top surfaces of the redistribution circuitstructure 230 may become doming-like top surfaces.

Each redistribution wiring of the redistribution circuit structure 230may include a base portion 230 a and a doming portion 230 b disposed onthe base portion 230 a, respectively. For example, the height of thebase portion 230 a ranges from about 10 micrometers to about 20micrometers, and the maximum height of the doming portion 230 b rangesfrom about 0.5 micrometer to about 3 micrometers.

After removing the solder material layers 240 from the top surfaces ofthe redistribution circuit structure 230, a dielectric layer 250 havinga planar top surface may be formed over the semiconductor wafer W2 tocover the post-passivation layer 226 and the redistribution circuitstructure 230. The dielectric layer 250 may be in contact with sidewallsof the base portions 230 a, doming-like top surfaces of the domingportions 230 b and the top surface of the post-passivation layer 226.The dielectric layer 250 may be a polyimide (PI) layer, a PBO layer, ora dielectric layer formed by other suitable organic dielectricmaterials. The dielectric layer 250 may be formed through chemical vapordeposition (CVD), physical vapor deposition (PVD), dispensing or othersuitable film deposition processes. Furthermore, the dielectric layer250 includes contact openings for exposing portions of theredistribution circuit structure 230.

Conductive pillars 255 (i.e. first conductive pillars) are formed on thedielectric layer 250 and electrically connected to the exposed portionsof the redistribution circuit structure 230 through the contact openingsdefined in the dielectric layer 250. In some embodiments, the width (ordiameter) of the contact openings defined in the dielectric layer 250ranges from about 5 micrometers to about 20 micrometers, the width ofthe conductive pillars 255 ranges from about 15 micrometers to about 40micrometers, and the height of the conductive pillars 255 ranges fromabout 50 micrometers to about 100 micrometers. In some embodiments, theaspect ratio of the conductive pillars 255 ranges from about 2 to about3.5. The conductive pillars 255 may be formed through a plating process.In some embodiments, a seed layer (e.g., Ti/Cu seed layer) is formed onthe dielectric layer 250 and revealed portions of the conductive pads222 through a sputter process; a patterned photoresist layer is formedon the sputtered seed layer, wherein the patterned photoresist layerincludes openings located above the redistribution circuit structure 230for exposing the sputtered seed layer; a plating process is performedsuch that the conductive pillars 255 is plated on the sputtered seedlayer exposed by the openings defined in the patterned photoresistlayer; the patterned photoresist layer is stripped; and portions of thesputtered seed layer which are not covered by the conductive pillars 255are removed through an etching process until the dielectric layer 250 isexposed.

Referring to FIG. 2D, at least one top tier semiconductor die 100illustrated in FIG. 1F is picked-up and placed on the semiconductorwafer W2. The top tier semiconductor die 100 may be attached on thedielectric layer 250 through the die attachment film 160. The conductivepillars 255 are arranged in array and distributed around the top tiersemiconductor die 100. In some embodiments, the height of the conductivepillars 255 is greater than the thickness of the top tier semiconductordie 100. In some other embodiments, the height of the conductive pillars255 is substantially equal to the thickness of the top tiersemiconductor die 100. In some alternative embodiments, the height ofthe conductive pillars 255 is less than the thickness of the top tiersemiconductor die 100, and the top surfaces of the conductive pillars255 is higher than or substantially leveled with the top surfaces of theconductive vias 130.

As illustrated in FIG. 2D, after the top tier semiconductor die 100 ispicked-up and placed on the semiconductor wafer W2, a pre-cut process S3is performed along intersected scribe lines SL2 of the semiconductorwafer W2 such that intersected grooves G2 are formed on a front surfaceof the semiconductor wafer W2. In some embodiments, the grooves G2 areformed through a non-contact cutting process performed along theintersected scribe lines SL2 of the semiconductor wafer W2. For example,the grooves G2 are formed through a laser grooving process performedalong the intersected scribe lines SL2 of the semiconductor wafer W2.The grooves G2 may extend through the interconnect structure 220, andportions of the semiconductor substrate 210 are revealed by the groovesG2.

Referring to FIG. 2D and FIG. 2E, after performing the pre-cut processS3, an insulating material is formed to on the semiconductor wafer W2 tocover the top tier semiconductor die 100 and the conductive pillars 255.The insulating material fills the grooves G2. The insulating materialmay be formed by an over-molding process or a film deposition process.After performing the over-molding process or film deposition process, agrinding process may be performed to partially remove the insulatingmaterial until the conductive vias 130 of the top tier semiconductor die100 and the top surfaces of the conductive pillars 255 are revealed.After the grinding process of the insulating material, an insulatingencapsulation 260 is formed over the semiconductor wafer W2 to laterallyencapsulate the top tier semiconductor die 100, the conductive pillars255 and the semiconductor substrate 210. In some embodiments, thegrinding process for partially removing the insulating material includesa mechanical grinding process, a CMP process, or combinations thereof.For example, the material of the insulating encapsulation 260 includesSilica, epoxy polymer or other suitable dielectric materials.

As illustrated in FIG. 2E, since the top tier semiconductor die 100 andthe conductive pillars 255 are laterally encapsulated by the insulatingencapsulation 260, the insulating encapsulation 260 may be merely incontact with the side surfaces of the top tier semiconductor die 100 andsidewalls of the conductive pillars 255. In some embodiments, asillustrated in FIG. 2E, the top surfaces of the top tier semiconductordie 100 and the conductive pillars 255 are substantially leveled withthe top surface of the insulating encapsulation 260. In some otherembodiments, the top surfaces of the top tier semiconductor die and theconductive pillars are slightly lower or slightly higher than the topsurface of the insulating encapsulation 260 due to grinding selectivity.

After forming the insulating encapsulation 260, a thinning process ofthe semiconductor wafer W2 is performed such that the semiconductorsubstrate 210 of the semiconductor wafer W2 is thinned down. In someembodiments, the semiconductor wafer W2 is flipped upside down, and thesemiconductor substrate 210 is thinned down from a back surface of thesemiconductor wafer W2 through a thinning process. In some embodiments,the semiconductor substrate 210 is thinned down through a mechanicalgrinding process, a CMP process, an etching process, combinationsthereof or other suitable removal processes.

Referring to FIG. 2E and FIG. 2F, after performing the thinning processof the semiconductor wafer W2, a die attachment film 270 may be attachedto the back surface of the semiconductor substrate 210. Then, a wafersawing process S4 is performed from the front surface of thesemiconductor wafer W2 to saw the insulating encapsulation 260, thesemiconductor wafer W2 and the die attachment film 270. The wafer sawingprocess S4 may be performed along the grooves G2 or the intersectedscribe lines SL2 of the semiconductor wafer W2 to obtain singulatedsemiconductor components SC1 having ring-shaped grooves G2′. The cuttingwidth of the pre-cut process S3 (illustrated in FIG. 2D) may be widerthan the cutting width of the wafer sawing process S4. In other words,the maximum lateral dimension of the grooves G2 (illustrated in FIG. 2E)may be wider than the cutting width of the wafer sawing process S4. Insome embodiments, the pre-cut process S3 is a laser grooving processwhile the wafer sawing process S4 is a blade saw process, wherein thecutting width of the pre-cut process S3 (e.g., the laser groovingprocess) is wider than the cutting width of the wafer sawing process S4(e.g., the blade saw process). Since the cutting width of the pre-cutprocess S3 (i.e. the maximum lateral dimension of the grooves G2) iswider than the cutting width of the wafer sawing process S4, theinterconnect structure 220 and the dielectric layer 250 of thesingulated bottom tier semiconductor die 200 may not be in contact withthe blade used in the wafer sawing process S4. Accordingly, the pre-cutprocess S3 (i.e. the grooves G2) may protect the interconnect structure220 and the dielectric layer 250 from being damaged during the wafersawing process S4.

As illustrated in FIG. 2F, the singulated semiconductor component SC1may include the bottom tier semiconductor die 200, the top tiersemiconductor die 100 stacked over the bottom tier semiconductor die200, the conductive pillars 255 and the insulating encapsulation 260.The singulated bottom tier semiconductor die 200 may include thesemiconductor substrate 210, the interconnect structure 220 disposed onthe semiconductor substrate 210 and the redistribution circuit structure230 disposed on the interconnect structure 220. The thickness of thesemiconductor substrate 210 may range from about 60 micrometers to about100 micrometers. The semiconductor substrate 210 may include a firstportion 210 a and a second portion 210 b disposed on the first portion210 a, wherein the interconnect structure 220 is disposed on the secondportion 210 b, and the lateral dimension of the first portion 210 a isgreater than the lateral dimension of the second portion 210 b. Thelateral dimension of the second portion 210 b and the lateral dimensionof the interconnect structure 220 are determined by the cutting width ofthe pre-cut process S3 (i.e. the maximum lateral dimension of thegrooves G2 or G2′) while the lateral dimension of the first portion 210a is determined by the cutting width of the wafer sawing process S4(e.g., the blade saw process). Since the redistribution circuitstructure 230 is merely distributed on the bottom tier semiconductor die200, the redistribution circuit structure 230 is a fan-in redistributioncircuit structure.

In some embodiments, in the singulated semiconductor component SC1, thelateral dimension of the top tier semiconductor die 100 is less thanthat of the bottom tier semiconductor die 200, wherein a minimumdistance between sidewalls of the top tier semiconductor die 100 andsidewalls of the bottom tier semiconductor die 200 may be greater than300 micrometers. In the singulated semiconductor component SC1, themaximum lateral dimension of the grooves G2′ illustrated in FIG. 2F mayrange from about 5 micrometers to about 30 micrometers, and the depth ofthe grooves G2′ illustrated in FIG. 2F may range from about 10micrometers to about 30 micrometers.

In the singulated semiconductor component SC1, the insulatingencapsulation 260 covers sidewalls of the second portion 210 b of thesemiconductor substrate 210, and sidewalls of the insulatingencapsulation 260 are substantially aligned with sidewalls of the firstportion 210 a of the semiconductor substrate 210. The insulatingencapsulation 260 may include a body portion 260 a and a ring portion260 b, wherein the body portion 260 a laterally encapsulates the toptier semiconductor die 100 and the conductive pillars 255, and the ringportion 260 b extends along sidewalls of the interconnect structure 220,sidewalls of the redistribution circuit structure 230 and the sidewallsof the second portion 210 b. The ring portion 260 b extend downwardlyinto the grooves G2′ from the bottom of the body portion 260 a.Furthermore, the sidewalls of the interconnect structure 220 may becovered and protected by the ring portion 260 b of the insulatingencapsulation 260. The ring portion 260 b laterally encapsulates thesecond portion 210 b of the semiconductor substrate 210.

Referring to FIG. 2F and FIG. 2G, the singulated semiconductor componentSC1 illustrated in FIG. 2F may be packed through an integrated fan-outpackaging process. In some embodiment, a back side fan-outredistribution circuit structure 300 (i.e. a second redistributioncircuit structure) is formed on a carrier (not shown); conductivepillars 310 (i.e. second conductive pillars) are formed on andelectrically connected to the back side fan-out redistribution circuitstructure 300, wherein the width of the conductive pillars 310 rangesfrom about 150 micrometers to about 250 micrometers, the height of theconductive pillars 310 ranges from about 150 micrometers to about 200micrometers, and the aspect ratio of the conductive pillars 310 rangesfrom about 1 to about 2; the singulated semiconductor component SC1 isthen picked-up and placed on the back side fan-out redistributioncircuit structure 300 such that the singulated semiconductor componentSC1 is attached onto the back side fan-out redistribution circuitstructure 300 through the die attachment film 270; the singulatedsemiconductor component SC1 and the conductive pillars 310 are laterallyencapsulated with an insulating encapsulation 320, wherein theinsulating encapsulation 320 may be formed by an over-molding processfollowed by a grinding process or a film deposition process followed bya grinding process, the material of the insulating encapsulation 320includes Silica, epoxy polymer or other suitable dielectric materials,and the coefficient of thermal expansion (CTE) of the insulatingencapsulation 320 is different from that of the insulating encapsulation260; a front side fan-out redistribution circuit structure 330 (i.e. athird redistribution circuit structure) is formed on the singulatedsemiconductor component SC1, the conductive pillars 310 and theinsulating encapsulation 320, wherein the back side fan-outredistribution circuit structure 300 and the front side fan-outredistribution circuit structure 330 are disposed at opposite sides ofthe conductive pillars 320, and the front side fan-out redistributioncircuit structure 330 may be electrically connected to the singulatedsemiconductor component SC1 through the back side fan-out redistributioncircuit structure 300 and the conductive pillars 310; and conductiveterminals 340 (e.g., solder balls) and passive components 350 (e.g.,resistors, inductors and/or capacitors) are formed on the front sidefan-out redistribution circuit structure 330.

As illustrated in FIG. 4, the insulating encapsulation 260 may furtherinclude another ring portion 260 c, wherein the ring portion 260 claterally extend from inner sidewalls of the body portion 260 a to fillsthe ring-shaped groove G1′. The ring portion 260 a and the ring portion260 c of the insulating encapsulation 260 may fill the grooves G1′ andG2′ respectively such that the interconnect structures 120, theinterconnect structure 220 and the redistribution circuit structure 230are in contact with and surrounded by the insulating encapsulation 260.The interconnect structure 120 is merely in contact with the ringportion 260 c of the insulating encapsulation 260. The interconnectstructure 220 and the redistribution circuit structure 230 are merely incontact with the ring portion 260 b of the insulating encapsulation 260.Since the insulating encapsulation 260 fills the grooves G2′, theinterconnect structure 220 and the redistribution circuit structure 230are spaced apart from the insulating encapsulation 320 by the ringportion 260 a of the insulating encapsulation 260. Furthermore, thesecond portion 210 b of the semiconductor substrate 210 is spaced apartfrom the insulating encapsulation 320 by the ring portion 260 a of theinsulating encapsulation 260, and the insulating encapsulation 320 ismerely in contact with the first portion 210 a of the semiconductorsubstrate 210.

As illustrated in FIG. 4, since the interconnect structure 120, theinterconnect structure 220 and the redistribution circuit structure 230are not simultaneously in contact with the insulating encapsulation 260and the insulating encapsulation 320 with different CTE, theinterconnect structure 120, the interconnect structure 220 and theredistribution circuit structure 230 may suffer less stress, andreliability of the interconnect structure 120, the interconnectstructure 220 and the redistribution circuit structure 230 may beimproved.

Referring to FIG. 2G and FIG. 2H, after the singulated semiconductorcomponent SC1 is packed through the integrated fan-out packagingprocess, a wafer-level package structure P1 is fabricated. At least onepackage P2 including conductive terminals 360 is provided and mounted onthe wafer-level package structure P1. In some embodiments, the packageP2 is a DRAM package, and the conductive terminals 360 includes solderballs. After mounting the at least one package P2 onto the wafer-levelpackage structure P1, the wafer-level package structure P1 the at leastone package P2 may be singulated to obtain at least onepackage-on-package (PoP) structure.

FIG. 5A through FIG. 5G are cross-sectional views schematicallyillustrating a process flow for fabricating a package structure inaccordance with some alternative embodiments of the present disclosure.FIG. 6 is an enlarged cross-sectional view of the region Z illustratedin FIG. 5G.

Referring to FIG. 5A, a semiconductor wafer W3 including bottom tiersemiconductor dies 400 (only one bottom tier semiconductor die 400 isshown in FIG. 5A for illustration) arranged in array is provided. Thesemiconductor wafer W3 may include a semiconductor substrate 410, aninterconnect structure 420 disposed on the semiconductor substrate 410and a bonding structure 430 disposed on the interconnect structure 420.The semiconductor substrate 410 may be a silicon substrate includingactive components (e.g., transistors or the like) and passive components(e.g., resistors, capacitors, inductors, or the like) formed therein.The active components and passive components are formed in thesemiconductor substrate 410 through front end of line (FEOL) fabricationprocesses of the semiconductor wafer W3. The interconnect structure 420may include interconnect wirings (e.g., copper interconnect wirings) anddielectric layer stacked alternately, wherein the interconnect wiringsof the interconnect structure 420 are electrically connected to theactive components and/or the passive components in the semiconductorsubstrate 410. The interconnect structure 420 is formed through back endof line (BEOL) fabrication processes of the semiconductor wafer W3. Thebonding structure 430 may include a bonding dielectric layer 430 a andbonding conductors 430 b embedded in the bonding dielectric layer 430 a.

As illustrated in FIG. 5A, the semiconductor wafer W3 may furtherinclude through semiconductor vias (TSVs) 440, wherein the throughsemiconductor vias 440 are electrically connected to the interconnectstructure 420 and the bonding structure 430. The through semiconductorvias 440 are embedded in the semiconductor substrate 430 and theinterconnect structure 420. Furthermore, the height of the throughsemiconductor vias 440 is less than the sum of the thickness of thesemiconductor substrate 430 and the thickness of the interconnectstructure 420.

In some embodiments, the semiconductor wafer W3 is a wafer includinglogic dies arranged in array. In some alternative embodiments, thesemiconductor wafer W3 is an interposer wafer including siliconinterposers arranged in array. Other types of semiconductor wafers maybe used in the present application.

Top tier semiconductor dies 500 are provided and bonded with thesemiconductor wafer W3. The top tier semiconductor dies 500 may eachinclude a semiconductor substrate 510, an interconnect structure 520disposed on the semiconductor substrate 510 and a bonding structure 530disposed on the interconnect structure 520. The second semiconductor dieis electrically connected to the first semiconductor die through thefirst and second bonding structures. The semiconductor substrate 510 maybe a silicon substrate including active components (e.g., transistors orthe like) and passive components (e.g., resistors, capacitors,inductors, or the like) formed therein. The active components andpassive components are formed in the semiconductor substrate 510 throughfront end of line (FEOL) fabrication processes of the semiconductorwafer. The interconnect structure 520 may include interconnect wirings(e.g., copper interconnect wirings) and dielectric layer stackedalternately, wherein the interconnect wirings of the interconnectstructure 520 are electrically connected to the active components and/orthe passive components in the semiconductor substrate 510. Theinterconnect structure 520 is formed through back end of line (BEOL)fabrication processes of the semiconductor wafer. The bonding structure530 may include a bonding dielectric layer 530 a and bonding conductors530 b embedded in the bonding dielectric layer 530 a.

A chip-to-wafer bonding process is performed such that the top tiersemiconductor dies 500 are bonded with the semiconductor wafer W3through the bonding structure 430 and the bonding structure 530. In someembodiments, a face-to-face hybrid bonding process is performed to bondthe top tier semiconductor dies 500 with the semiconductor wafer W3.After performing the bonding process, the bonding dielectric layer 430 aof the semiconductor wafer W3 is bonded with the bonding dielectriclayers 530 a of the top tier semiconductor dies 500, and the bondingconductors 430 b of the semiconductor wafer W3 are bonded with thebonding conductors 530 b of the top tier semiconductor dies 500.

Referring to FIG. 5B, after the top tier semiconductor dies 500 arepicked-up and placed on the semiconductor wafer W3, a pre-cut process isperformed along intersected scribe lines of the semiconductor wafer W3such that intersected grooves G3 are formed on a front surface of thesemiconductor wafer W3. In some embodiments, the grooves G3 are formedthrough a non-contact cutting process performed along the intersectedscribe lines of the semiconductor wafer W3. For example, the grooves G3are formed through a laser grooving process performed along theintersected scribe lines of the semiconductor wafer W3. The grooves G3may extend through the interconnect structure 420, and portions of thesemiconductor substrate 410 are revealed by the grooves G3.

After performing the pre-cut process, an insulating material 600 isformed to on the semiconductor wafer W3 to cover the top tiersemiconductor dies 500. The insulating material 600 fills the groovesG3. The insulating material 600 may be formed by an over-molding processor a film deposition process. After performing the over-molding processor film deposition process, a first grinding process may be performed toreduce the thickness of the insulating material 600.

Referring to FIG. 5B and FIG. 5C, after the first grinding process ofthe insulating material 600 is performed, an insulating encapsulation600 a is formed over the semiconductor wafer W3 to encapsulate the toptier semiconductor dies 500. In some embodiments, the first grindingprocess for partially removing the insulating material 600 includes amechanical grinding process, a CMP process, or combinations thereof.

Referring to FIG. 5C and FIG. 5D, the resulted structure illustrated inFIG. 5C is mounted onto a carrier 700 through a die attachment film 710.The insulating encapsulation 600 a may be attached to the carrier 700through the die attachment film 710. Then, a thinning process of thesemiconductor wafer W3 is performed such that the semiconductorsubstrate 410 of the semiconductor wafer W3 is thinned down, andportions of the through semiconductor vias 440 are revealed at a backsurface of the semiconductor wafer W3. In some embodiments, thesemiconductor wafer W3 is flipped upside down, and the semiconductorsubstrate 410 is thinned down from a back surface of the semiconductorwafer W3 through a thinning process. In some embodiments, thesemiconductor substrate 410 is thinned down through a mechanicalgrinding process, a CMP process, an etching process, combinationsthereof or other suitable removal processes.

Referring to FIG. 5E, after performing the thinning process of thesemiconductor wafer W3, a dielectric layer 450 (e.g., silicon nitridelayer) covering the back surface of the semiconductor wafer W3 andconductive vias 460 electrically connected to the through semiconductorvias 440 are formed. Then, a frame mount process may be performed suchthat the semiconductor wafer W3 including the dielectric layer 450 andthe conductive vias 460 formed thereon may be mounted on and attached toa frame, and the carrier 700 and the die attachment film 710 arede-bonded from the insulating encapsulation 600 a.

Referring to FIG. 5E and FIG. 5F, after performing the de-bondingprocess of the carrier 700 and the die attachment film 710, thedielectric layer 450 and the conductive vias 460 may be attached to atape 720, and a second grinding process is performed to reduce thethickness of the insulating material 600 a until the top tiersemiconductor dies 500 are revealed. Then, a die attachment film 610 maybe provided and attached to the top surface of the insulating material600 a and the revealed surfaces of the top tier semiconductor dies 500.

A wafer sawing process S5 is performed from the back surface of thesemiconductor wafer W3 to saw tape 720, the semiconductor wafer W3 andthe insulating encapsulation 600 a. The wafer sawing process S5 may beperformed along the grooves G3 or the intersected scribe lines of thesemiconductor wafer W3 to obtain multiple singulated semiconductorcomponents SC2 having grooves G3′. The cutting width of the pre-cutprocess (illustrated in FIG. 5B) may be wider than the cutting width ofthe wafer sawing process S5. In other words, the maximum lateraldimension of the grooves G3 (illustrated in FIG. 5B) may be wider thanthe cutting width of the wafer sawing process S5. In some embodiments,the pre-cut process is a laser grooving process while the wafer sawingprocess S5 is a blade saw process, wherein the cutting width of thepre-cut process (e.g., the laser grooving process) is wider than thecutting width of the wafer sawing process S5 (e.g., the blade sawprocess). Since the cutting width of the pre-cut process (i.e. themaximum lateral dimension of the grooves G3) is wider than the cuttingwidth of the wafer sawing process S5, the interconnect structure 420 andthe bonding structure 430 of the singulated bottom tier semiconductordie 400 may not be in contact with the blade used in the wafer sawingprocess S5. Accordingly, the pre-cut process (i.e. the grooves G3) mayprotect the interconnect structure 420 and the bonding structure 430from being damaged during the wafer sawing process S5.

Referring to FIG. 5F and FIG. 5G, each singulated semiconductorcomponent SC2 may include the bottom tier semiconductor die 400, the toptier semiconductor dies 500 stacked over the bottom tier semiconductordie 400 and the insulating encapsulation 600 a. The singulated bottomtier semiconductor die 400 may include the semiconductor substrate 410,the interconnect structure 420 disposed on the semiconductor substrate410 and the bonding structure 430 disposed on the interconnect structure420. The thickness of the semiconductor substrate 410 may range fromabout 10 micrometers to about 100 micrometers. The semiconductorsubstrate 410 may include a first portion 410 a and a second portion 410b disposed on the first portion 410 a, wherein the interconnectstructure 420 is disposed on the second portion 410 b, and the lateraldimension of the first portion 410 a is greater than the lateraldimension of the second portion 410 b. The lateral dimension of thesecond portion 410 b and the lateral dimension of the interconnectstructure 420 are determined by the cutting width of the pre-cut process(i.e. the maximum lateral dimension of the grooves G3 or G3′) while thelateral dimension of the first portion 410 a is determined by thecutting width of the wafer sawing process (e.g., the blade saw process).

In some embodiments, in the singulated semiconductor component SC2, thelateral dimension of the top tier semiconductor dies 500 is less thanthat of the bottom tier semiconductor die 400. In the singulatedsemiconductor component SC2, the maximum lateral dimension of thegrooves G3′ illustrated in FIG. 5F may range from about 5 micrometers toabout 30 micrometers, and the depth of the grooves G3′ illustrated inFIG. 5F may range from about 10 micrometers to about 30 micrometers.

In the singulated semiconductor component SC2, the insulatingencapsulation 600 a covers sidewalls of the second portion 410 b of thesemiconductor substrate 410, and sidewalls of the insulatingencapsulation 600 a are substantially aligned with sidewalls of thefirst portion 410 a of the semiconductor substrate 410. The insulatingencapsulation 600 a may include a body portion 600 a 1 and a ringportion 600 a 2, wherein the body portion 600 a 1 laterally encapsulatesthe top tier semiconductor dies 500, and the ring portion 600 a 2extends along sidewalls of the interconnect structure 420, sidewalls ofthe bonding structure 430 and the sidewalls of the second portion 410 b.The ring portion 600 a 2 extend into the grooves G3′ from the bottom ofthe body portion 600 a 1. Furthermore, the sidewalls of the interconnectstructure 420 may be covered and protected by the ring portion 600 a 2of the insulating encapsulation 600 a. The ring portion 600 a 2laterally encapsulates the second portion 410 b of the semiconductorsubstrate 410.

Referring to FIG. 5F and FIG. 5G, the singulated semiconductor componentSC2 illustrated in FIG. 5F may be packed through an integrated fan-outpackaging process. In some embodiment, a fan-out redistribution circuitstructure 800 is formed on a carrier (not shown); conductive pillars 810are formed on and electrically connected to the fan-out redistributioncircuit structure 800, wherein the width of the conductive pillars 810ranges from about 150 micrometers to about 250 micrometers, the heightof the conductive pillars 810 ranges from about 150 micrometers to about200 micrometers, and the aspect ratio of the conductive pillars 810ranges from about 1 to about 2; the singulated semiconductor componentSC2 is then picked-up and placed on the fan-out redistribution circuitstructure 800 such that the singulated semiconductor component SC2 isattached onto the fan-out redistribution circuit structure 800 throughthe die attachment film 610; the singulated semiconductor component SC2and the conductive pillars 810 are laterally encapsulated with aninsulating encapsulation 820, wherein the insulating encapsulation 820may be formed by an over-molding process followed by a grinding processor a film deposition process followed by a grinding process; a fan-outredistribution circuit structure 830 (i.e. a third redistributioncircuit structure) is formed on the singulated semiconductor componentSC2, the conductive pillars 810 and the insulating encapsulation 820,wherein the fan-out redistribution circuit structure 800 and the fan-outredistribution circuit structure 830 are disposed at opposite sides ofthe conductive pillars 820, and the fan-out redistribution circuitstructure 800 may be electrically connected to the singulatedsemiconductor component SC2 through the fan-out redistribution circuitstructure 830 and the conductive pillars 810; and conductive terminals840 (e.g., solder balls) are formed on the fan-out redistributioncircuit structure 830.

As illustrated in FIG. 6, the insulating encapsulation 600 a may fillthe grooves G3′ such that the interconnect structure 420 and the bondingstructure 430 are in contact with and surrounded by the insulatingencapsulation 600 a. Since the insulating encapsulation 600 a fills thegrooves G3′, the interconnect structure 420, the bonding structure 430and the bonding structure 530 are spaced apart from the insulatingencapsulation 820 by the insulating encapsulation 600 a. Furthermore,the second portion 410 b of the semiconductor substrate 410 is spacedapart from the insulating encapsulation 820 by the insulatingencapsulation 600 a, and the insulating encapsulation 820 is merely incontact with the first portion 410 a of the semiconductor substrate 410.In some embodiments, the second portion 410 b of the semiconductorsubstrate 410 is spaced apart from the insulating encapsulation 820 bythe ring portion 600 a 2 of the insulating encapsulation 600 a. In someembodiments, the top tier semiconductor dies 500 are spaced apart fromthe insulating encapsulation 820 by a distance (e.g., greater than 50micrometers) defined by the body portion 600 a 1 of the insulatingencapsulation 600 a.

As illustrated in FIG. 6, since the interconnect structure 420, theinterconnect structure 520, the bonding structure 430 and the bondingstructure 530 are not simultaneously in contact with the insulatingencapsulation 600 a and the insulating encapsulation 820 with differentCTE, the interconnect structure 420, the interconnect structure 520, thebonding structure 430 and the bonding structure 530 may suffer lessstress, and reliability of the interconnect structure 420, theinterconnect structure 520, the bonding structure 430 and the bondingstructure 530 may be improved.

Referring to FIG. 5G, after the singulated semiconductor component SC2is packed through the integrated fan-out packaging process, awafer-level package structure P3 is fabricated. At least one package P4including conductive terminals 860 is provided and mounted on thewafer-level package structure P3. In some embodiments, the package P4 isa DRAM package, and the conductive terminals 860 includes solder balls.After mounting the at least one package P4 onto the wafer-level packagestructure P3, the wafer-level package structure P3 and the at least onepackage P4 may be singulated to obtain at least one package-on-package(PoP) structure.

In accordance with some embodiments of the disclosure, a packagestructure including a first semiconductor die, a second semiconductordie, first conductive pillars and a first insulating encapsulation isprovided. The first semiconductor die includes a semiconductorsubstrate, an interconnect structure and a first redistribution circuitstructure. The semiconductor substrate includes a first portion and asecond portion disposed on the first portion, wherein the interconnectstructure is disposed on the second portion, the first redistributioncircuit structure is disposed on and electrically connected to theinterconnect structure, and a first lateral dimension of the firstportion is greater than a second lateral dimension of the secondportion. The second semiconductor die is disposed on the firstsemiconductor die. The first conductive pillars are disposed on andelectrically connected to the first redistribution circuit structure ofthe first semiconductor die. The first insulating encapsulation isdisposed on the first portion. The first insulating encapsulationlaterally encapsulates the second semiconductor die, the firstconductive pillars and the second portion. In some embodiments, thefirst insulating encapsulation covers sidewalls of the second portion,and sidewalls of the first insulating encapsulation are substantiallyaligned with sidewalls of the first portion. In some embodiments, thefirst insulating encapsulation includes a body portion and a ringportion, the body portion laterally encapsulates the secondsemiconductor die and the first conductive pillars, the ring portionextends along sidewalls of the interconnect structure, sidewalls of thefirst redistribution circuit structure and the sidewalls of the secondportion. In some embodiments, the package structure further includessecond conductive pillars, a second insulating encapsulation and asecond redistribution circuit structure, wherein second insulatingencapsulation laterally encapsulates the second conductive pillars, thefirst insulating encapsulation and the first portion. The secondredistribution circuit structure is disposed on the second semiconductordie. The first conductive pillars, the second conductive pillars, thefirst insulating encapsulation and the second insulating encapsulation.In some embodiments, the first redistribution circuit structure is afan-in redistribution circuit structure, and the second redistributioncircuit structure is a fan-out redistribution circuit structure. In someembodiments, the interconnect structure and the first redistributioncircuit structure are spaced apart from the second insulatingencapsulation by the first insulating encapsulation. In someembodiments, the package structure further includes a thirdredistribution circuit structure disposed over the first portion, thesecond conductive pillars and the second insulating encapsulation,wherein the second and third redistribution circuit structures aredisposed at opposite sides of the second conductive pillars.

In accordance with some other embodiments of the disclosure, a packagestructure including a first semiconductor die, a second semiconductordie and a first insulating encapsulation. The first semiconductor dieincludes a first semiconductor substrate, a first interconnect structureand a first bonding structure. The first semiconductor substrateincludes a first portion and a second portion disposed on the firstportion. The first interconnect structure is disposed on the secondportion, the first bonding structure is disposed on and electricallyconnected to the first interconnect structure, and a first lateraldimension of the first portion is greater than a second lateraldimension of the second portion. The second semiconductor die includes asecond semiconductor substrate, a second interconnect structure disposedon the second semiconductor substrate and a second bonding structuredisposed on the second interconnect structure. The second semiconductordie is electrically connected to the first semiconductor die through thefirst and second bonding structures. The first insulating encapsulationis disposed on the first portion of the first semiconductor substrate,and the first insulating encapsulation laterally encapsulates the secondsemiconductor die and the second portion of the first semiconductorsubstrate. In some embodiments, the first insulating encapsulationcovers sidewalls of the second portion of the first semiconductorsubstrate, and sidewalls of the first insulating encapsulation aresubstantially aligned with sidewalls of the first portion of the firstsemiconductor substrate. In some embodiments, the first insulatingencapsulation includes a body portion and a ring portion, the bodyportion laterally encapsulating the second semiconductor die, the ringportion extending along sidewalls of the interconnect structure,sidewalls of the first bonding structure and the sidewalls of the secondportion of the first semiconductor substrate. In some embodiments, thepackage structure further includes conductive pillars, a secondinsulating encapsulation and a first fan-out redistribution circuitstructure. The second insulating encapsulation laterally encapsulatesthe conductive pillars, the first insulating encapsulation and the firstportion of the first semiconductor substrate. The first fan-outredistribution circuit structure is disposed on the second insulatingencapsulation and electrically connected to the first semiconductor dieand the conductive pillars. In some embodiments, the first semiconductordie includes through semiconductor vias electrically connected to thefirst redistribution circuit structure. In some embodiments, the firstinterconnect structure, the second interconnect structure, the firstbonding structure and the second bonding structure are spaced apart fromthe second insulating encapsulation by the first insulatingencapsulation. In some embodiments, the package structure furtherincludes a second fan-out redistribution circuit structure disposed onthe second semiconductor die, the conductive pillars, the firstinsulating encapsulation and the second insulating encapsulation. Insome embodiments, the package structure further includes a dieattachment film disposed between the second semiconductor die and thesecond fan-out redistribution circuit structure.

In accordance with some other embodiments of the disclosure, a methodincluding the followings is provided. Upper tier semiconductor dies areplaced to a semiconductor wafer including bottom tier semiconductordies, wherein the semiconductor wafer includes a semiconductor substrateand an interconnect structure disposed on the semiconductor substrate.Grooves are formed on the semiconductor wafer, wherein the groovesextend through the interconnect structure, and the semiconductorsubstrate is revealed by the grooves. An insulating encapsulation isformed over the semiconductor wafer to laterally encapsulate the uppertier semiconductor dies and fill the grooves. A wafer sawing process isperformed to saw the insulating encapsulation and the semiconductorwafer along scribe lines of the semiconductor wafer, wherein a maximumlateral dimension of the grooves is wider than a cutting width of thewafer sawing process. In some embodiments, the grooves are formed afterplacing the upper tier semiconductor dies to the semiconductor wafer. Insome embodiments, the grooves are formed through a non-contact cuttingprocess performed along the scribe lines of the semiconductor wafer. Insome embodiments, the grooves are formed through a laser groovingprocess performed along the scribe lines of the semiconductor wafer, thewafer sawing process includes a blade saw process, and a first cuttingwidth of the laser grooving process is wider than a second cutting widthof the blade saw process. In some embodiments, the laser groovingprocess and the blade saw process are subsequently performed on a firstsurface of the semiconductor wafer on which the upper tier semiconductordies are placed. In some embodiments, the laser grooving process isperformed on a first surface of the semiconductor wafer on which theupper tier semiconductor dies are placed, the blade saw process isperformed from a second surface of the semiconductor wafer, and thefirst surface is opposite to the second surface.

The foregoing outlines features of several embodiments so that thoseskilled in the art may better understand the aspects of the presentdisclosure. Those skilled in the art should appreciate that they mayreadily use the present disclosure as a basis for designing or modifyingother processes and structures for carrying out the same purposes and/orachieving the same advantages of the embodiments introduced herein.Those skilled in the art should also realize that such equivalentconstructions do not depart from the spirit and scope of the presentdisclosure, and that they may make various changes, substitutions, andalterations herein without departing from the spirit and scope of thepresent disclosure.

What is claimed is:
 1. A method, comprising: placing upper tiersemiconductor dies to a semiconductor wafer comprising bottom tiersemiconductor dies, the semiconductor wafer comprising a semiconductorsubstrate and an interconnect structure disposed on the semiconductorsubstrate; forming grooves on the semiconductor wafer, the groovesextending through the interconnect structure, and the semiconductorsubstrate being revealed by the grooves; forming an insulatingencapsulation over the semiconductor wafer to laterally encapsulate theupper tier semiconductor dies and fill the grooves; and performing awafer sawing process to saw the insulating encapsulation and thesemiconductor wafer along scribe lines of the semiconductor wafer,wherein a maximum lateral dimension of the grooves is wider than acutting width of the wafer sawing process.
 2. The method as claimed inclaim 1, wherein the grooves are formed after placing the upper tiersemiconductor dies to the semiconductor wafer, and the grooves areformed through a non-contact cutting process performed along the scribelines of the semiconductor wafer.
 3. The method as claimed in claim 1,wherein the grooves are formed through a laser grooving processperformed along the scribe lines of the semiconductor wafer, the wafersawing process comprises a blade saw process, and a first cutting widthof the laser grooving process is wider than a second cutting width ofthe blade saw process.
 4. The method as claimed in claim 3, wherein thelaser grooving process and the blade saw process are subsequentlyperformed on a first surface of the semiconductor wafer on which theupper tier semiconductor dies are placed.
 5. The method as claimed inclaim 3, wherein the laser grooving process is performed on a firstsurface of the semiconductor wafer on which the upper tier semiconductordies are placed, the blade saw process is performed from a secondsurface of the semiconductor wafer, and the first surface is opposite tothe second surface.